Modelling of P-I-N Photodiodes Under High Illumination Conditions

Abstract-Nonlinearity in p-i-n photodetectors leads to power generation at harmonics of the input frequency, limiting the performance of RF-photonic systems. We use one-dimensional and two-dimensional simulations of the drift-diffusion equations to determine the physical origin of the saturation in a simple heterojunction p-i-n photodetector at room temperature. Incomplete ionization, external loading, impact ionization, and the Franz-Keldysh effect are all included in the model. Impact ionization is the main source of nonlinearity at large reverse bias (>10 V in the device that we simulated). The electron and hole current contributions to the second harmonic power were calculated. We find that impact ionization has a greater effect on the electrons than it does on the holes. We also find that the hole velocity saturates slowly with increasing reverse bias, and the hole current makes a large contribution to the harmonic power at 10 V. This result implies that decreasing the hole injection will decrease the harmonic power.Index Terms-2D simulation, impact ionization, nonlinearity, p-i-n photodetector.

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“…This case does not appear in our structure. Using (17), the current at the heterojunction can be written as…”

Section: A 1d Computational Modelmentioning

confidence: 99%

Modeling Sources of Nonlinearity in a Simple p-i-n Photodetector

Marks

Menyuk

et al. 2014

J. Lightwave Technol.

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“…The DD equations were chosen as the model framework in which to test the above explanation for the following reasons. Firstly, the most important factor in this case is the way the high photo-carrier densities modify the builtin electric field, which a DD model has been shown to approximate well, in the absence of impact ionization [5].…”

Section: Justification Of Modelmentioning

confidence: 99%

Mechanism of impact ionization enhancement in GaAs p-i-n diodes under high illumination conditions

Wilson¹,

Walker²

1998

Semicond. Sci. Technol.

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Recent experimental work on AlGaAs p-i-n photodiodes [Dudley R Aand Vickers A J 1995 Proc. Hot Carriers in Semiconductors IX (New York: Plenum)] has generated evidence that the transient photocurrent produced by high-intensity pulsed laser illumination is larger than expected for any given value of the bias. It has been postulated that this enhancement is due to the modification of the internal electric field by the photogenerated charge. A similar effect has been seen in calculations for metal-semiconductor-metal semiconductors [Dunn G M, Rees G J and David J P R 1997 Semicond. Sci. Technol. 12 692-7], but we present here details of the first calculation of the effect in a p-i-n diode. A drift-diffusion model is used to calculate photocurrent versus reverse bias for several values of illumination intensity, illustrating the enhancement effect. The origin of the enhancement is then highlighted and explained.

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Non-unique solutions in drift diffusion modelling of phototransistors

Woods

Wilson

Walker

2000

Int. J. Numer. Model.

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We report non‐unique solutions for the potential in a Drift Diffusion (DD) model of a two terminal phototransistor. These solutions are present under bias without illumination, and persist until high illumination levels. It is well known that the DD equations can yield non‐unique solutions for pn structures which contain three or more junctions and two terminals with applied biases greater than kBT log 2 where kBT is the thermal energy at a temperature T, but DD models of phototransistors under illumination have been less well studied. The implicit belief is that one needs to artificially impose a potential in the base of the phototransistor in order to obtain a unique solution. We show here that this is only necessary because of a weakness in the numerical methods used to solve the equations, and describe two methods which circumvent this for which we show that this problem does not occur. These methods are used to investigate the operation of GaAs and In0·53Ga0·47As homojunction phototransistors, including the influence of the position of the illumination region and base doping. Copyright © 2000 John Wiley & Sons, Ltd.

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Modelling of P-I-N Photodiodes Under High Illumination Conditions

Cited by 8 publications

References 13 publications

Modeling Sources of Nonlinearity in a Simple p-i-n Photodetector

Modeling Sources of Nonlinearity in a Simple p-i-n Photodetector

Mechanism of impact ionization enhancement in GaAs p-i-n diodes under high illumination conditions

Non-unique solutions in drift diffusion modelling of phototransistors

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